The present study aimed to indentify some bacterial isolates isolated from Egyptian soil and to investigate their susceptibility to malathion (organophosphorus insecticide), granstar (sulfonylurea herbicide), and topik (aryloxyphenoxypropionate herbicide) with the relation to general esterase activity. Fifty-six bacterial isolates have been isolated from agricultural soil previously treated with malathion (from Diarb Negm City), granstar (from Zagazig City), and topik (from Hehia City). All isolates were morphologically characterized and tested for their antibiotic susceptibility against tendifferent antibiotics of ampicillin, amoxicillin, cefadroxil, ceftriaxone, cefoperazone, cephradine, chloramphenicol, gentamycin, streptomycin, and tetracycline. Bioassay experiments using the tested pesticides were carried out to determine median inhibition concentrations (IC50s) for twenty bacterial isolates. Among the tested bacterial isolates, M18, G13, and T6 were found the most tolerant strains to malathion, granstar, and topik with IC50 of 730, 4782, and 469 µg ml-1, respectively. Esterase activity was measured in the growth medium as an indicator of degradative ability of isolates when exposed to IC50 values of the tested pesticides at 0, 12, 24, and 48 hr., of exposure. All isolates, except M1, showed a significant increase in esterase activity after 12 or 24 hr. of incubation with the tested pesticides, while significant decrease was obtained after 48 hr. of incubation. Three isolates have been chosen and identified by 16S rRNA technique. Based on the results of 16S rRNA genes sequences, the three isolates of M18, G4, and T8 were found to belong to the genus Enterobacter. Plasmid curing results showed that the genes responsible for pesticides degradation were located on the bacterial chromosome. Therefore, M18 isolate consider as a promising isolate in bioremediation activity.